getting count of method params

[neeha]

Hi Experts,
I am reading a java program through perl.
The code has something like

public void check1(String str,String str1)

Is there any way by which i can get the count of params of the "check1" method using perl.

[izut]

You can read perlre and perlretut. I would start with something like this, assuming all methods definition will be in one line:

while (<DATA>) {
    if (/^                  # Matches line start
        \s*                 # None or many spaces
        (?:public|private)? # Matches 'public', 'private' or none (pac
+kages)
        \s+                 # One or many spaces
        (?:\S+)             # Matches one or more non spacing chars (v
+ariable type)
        \s+                 # One or many spaces
        (?:\S+)             # Matches one or more non spacing chars (m
+ethod name)
        \s*                 # None or many spaces
        \(                  # Literal '('
            (.*)            # Matches everything
        \)                  # Literal ')'
        \s*                 # None or many spaces
        $                   # Matches end of line
        /x) {
                print $1, "\n";
        }
}

__DATA__

public void check1(String str, Integer i) 
{

}

[rafl]

Parameters to Java methods are usually enclosed between brackets and seperated by commas, right?

So how about extracting the part between the brackets and spliting that part at the comma? The number of elements in the list returned by split should tell you how many arguments a given method could take.

Cheers, Flo

[neeha]

I was doing it that way only.But my code looks quite lengthy.Is there any regular expressions by which i can achieve it.I am not that experienced in Perl so wanted to know if we can achive it in a short way.

[unobe]

My java is a little rusty, but IIRC a method always has an optional access modifier at the start, then the return type, and then the method name (followed by the parameters). A one liner that might help is (very ugly):

grep { print scalar (@params = /^\s*(?:(?:public|private|protected)\s+
+)?\w+\s+\w+\s*\(([^,]+)(\,[^,]+)*\)/g);} <>;

If you save the above code as test.pl, then running

perl test.pl FILENAME

will give you the number of parameters for each method. The diamond operator will automatically fetch the contents of whatever file you pass to the script at the command line (or STDIN, if no file supplied). The above code, made easier to read:

grep {
    print scalar # print the number of items matched
              (@params
                  = /^
                      # any whitespace at start of line
                      \s*

                      #optional access modifier
                      (?:(?:public|private|protected)\s+)

                      # return type and method name
                      \w+\s+\w+\s*

                      \(
                        # params separated by commas
                        ([^,]+)(\,[^,]+)* 
                      \)

                     # don't really need m or s
                     # since only one line is read at a time,
                     # but I find it a good habit to always
                     # use them
                    /gxms);
} <>; # read from keyboard or the file(s) provided on command line

I second izut's suggestion: read the perldocs.